MODEL "1164" BACK PRESSURE RELIEF REGULATOR,ARAMID/SBR GASKETS 1" SIZE; DUCTILE IRON BODY,CAST IRON SPRING CHAMBER; S5 TRIM: 316SST TRIM WITH TFE SEAT,PHOS.BRONZE DIAPHRAGM; NPT SCREWED; 10-40 PSIG RANGE SPRING; OPT-25: 1/4" NPT SPRING CHAMBER VENT TAP;